ARM: dts: msm: Add device tree support for board variants of QCS403

Add board specific dts files of qcs403 variants and while at it
also reorganize soc specific changes.

Change-Id: I4687fa1b1dae4df932fcee40c7ee7eed5c89b8b8
Signed-off-by: Avaneesh Kumar Dwivedi <akdwived@codeaurora.org>